Drill grinding tool



June 7, 1938. w H. FISCHER DRILL GRINDING TOOL Filed March 24, 1937Patented June 7, 1938 UNITED STATES PATENT O F 7 1 Claim.

One object of this invention is the provision of a drill grinding tooladapted to be mounted on a standard adjacent the grinding wheel, and soconstructed and designed that it may be quickly and deftly manipulatedto turn the drill through an arc of 180 degrees so as to have first onecutting edge of the drill against the wheel and then the oppositecutting edge with positive assurance that both edges willbe ground true.

Another object of the invention is the provision of such a device withmeans for feeding the drill toward the wheel and for retracting thedrill from the wheel in a very fine degree of movement, so as to avoidtoo great an advance toward the wheel when such adjustment is desired,and thereby prevent damage to either the wheel or the drill.

The above and other objects will become apparent in the descriptionbelow, in which characters of reference refer to like-named parts in theaccompanying drawing.

Referring briefly to the drawing, Figure 1 is a plan view of the devicemounted on a standard bearing the grinding wheel.

2 Figure 2 is a fragmentary side elevational view of Figure 1, with thetool in grinding position.

Figure 3 is a view similar to Figure 2, with the tool in elevatedposition prior to rotation thereof through an arc of 180 degrees.

30 Figure 4 is a cross-sectional view taken on the line 4-4 of Figure 1.

Figure 5 is a cross-sectional view taken on the line 55 of Figure 2.

Figure 6 is a cross-sectional View taken on the 35 line 6-6 of Figure 4.

Figure 7 is a front elevational view of the device.

Referring in detail to the drawing, the numeral It indicates a standardon which a rotat- LO able grindstone, emery wheel, or the like II ismounted. A fastening screw or the like I2 is provided on the standard Infor securing the grinding tool thereto.

The tool embodies a rectangular frame l3 hav- 5 ing an opening I4passing therethrough. The lower member I5 of the frame I3 is extendedangularly rearward of the frame 13 and formed into a yoke l6 by means ofwhich the device may be secured by the screw l2 to the standard 0 Ill.Screws I! pass through the sides of the frame I3 near the top thereof,and have tapered ends l8 which serve as pivots or trunnions for a blockl9 provided with complementary openings in which the trunnions l8register, thus 5 causing the block l9 to be pivotably suspendeddiametrically opposite points with indentations 5 7 2|. In the corner oredge of the block l9, a

channel 22 extending substantially radially with respect to the sleeve26, is provided through the block IS. A pin 23 is slidably mounted inthe channel 22 and urged toward the sleeve 20 by 10 a spring 24. Thetapering extremity of the pin 23, as well as the tapering form of theindentations 2|, permits releasable locking of the sleeve 20 againstrotation when the rotating force applied to the cap is relatively light,but 15 permits the sides of the indentations 2| to force the pin 23 outof the same, with consequent rotation of the sleeve, when the rotatingforce is relatively strong.

The sleeve 26 is provided with an extending 0 externally threaded body25 which threadably receives a barrel 26. open at both ends. A rigid pin21 projects internally into the barrel at a point intermediate itslength. The outer surface of the barrel 26 is knurled. A stud 28 havinga 25 rigid collar 29 intermediate its length, is mounted in the rear ofthe barrel 26 with oneend 30 projecting outward through the rear opening3! of the barrel. Both the forward end 32 and the rearward end 30 of thestud 28, are'threaded. 30 A reduced knob 33 whose outer surface is alsoknurled, is tightly screwed on the stud end 30 and locked therein by apin 40 so that the stud 28 is locked thereon and rotates unitarily withthe knob 33.

A hollow stem 34 has its rear end 35 enlarged and provided on its outersurface with a longitudinal slot 36 in which the pin 27 registers. Theend 35 of the stem 36 is internally threaded and engageable on theforward end 32 of the 40 stud 38. It is to be noted that because of theengagement of the pin 21 in the slot 36, rotation of the stud 28 by theknob 33 will cause the stem 34 to moveforward or backward along 7 itsaxis. A spring 3'! surrounds the stem 34 be- 4 tween the body 25 of thesleeve 26 and the shoulder formed by the junction of the stem 34 withits enlarged end 35. This spring normally urges the stem 34 rearwardfrom the sleeve 26. At the forward end of the stem '34, a chuck 33 isprovided which is of standard construction and serves to receive andlocktherein the drill which is to be ground. The manner of assemblingthe entire tool is obvious from the above. In use, the drill 39 is 5locked in the chuck 38 after the device has been secured to the standardIll. The relative position of the tool with respect to the wheel II isroughly adjusted by means of the screw l2 and the yoke l6. Fineadjustment in advancing or retracting the drill from the wheel is madeby rotation of the knob 33.

To obtain correct results in sharpening a drill, both surfaces of thedrill must be ground exactly alike from the center. Usually this is ahit-and-miss matter, especially in grinding small drills. To use thetool described, the cutting edge of the drill is placed in horizontalposition, and the drill is advanced slowly to the wheel H by turning theknob 33, and one cutting edge of the drill is ground. The tool is thenswung downward on its pivots 18 to carry the drill clear of the wheel.The barrel 26 is then rotated through half a turn, which is checkedwithout any possibility of doubt by the clicking of the pin 23 as itsnaps into the diametrically opposite indentation 2|. Then the tool withits opposite edge facing the wheel, is again advanced to the wheel bymeans of the knob 33. Thus, proper and accurate grinding of bothopposite edges of the drill is assured.

Obviously, modifications in form and structure may be made withoutdeparting from the spirit and scope of the invention.

I claim:

A drill grinding tool comprising a substantially rectangular uprightframe, means for securing said frame on a standard, a block pivotallysuspended within said frame, said block having a circular openingtherethrough in the upper portion thereof, a sleeve rotatably mounted insaid opening, a barrel secured to and extending axially rearward of saidsleeve, a stem slidably mounted in said sleeve and having a chuck on itsforward end, a knob rotatably mounted at the rear end of said barrel,means between said stem and said knob for advancing or retarding saidstem upon rotation of said knob, said sleeve having a pair of oppositelydisposed cone-shaped indentations on its outer surface within saidblock, a tapered pin slidably mounted in said block and projectingsubstantially radially into said opening, a spring urging said pintoward said opening, said pin being adapted to register alternately insaid indentations.

WILLIAM H. FISCHER.

